Sri Lanka makes rights progress: Abbott

Prime Minister Tony Abbott won't be joining other world leaders in a boycott of the Commonwealth summit, saying Australia shouldn't be giving lectures to other countries about human rights.

The prime ministers of Canada and India are boycotting the Commonwealth Heads of Government Meeting (CHOGM), which will be opened by Prince Charles in the Sri Lankan capital Colombo on Friday.

Other leaders including British PM David Cameron have resisted domestic political pressure not to make the trip, arguing it is better to engage the island nation rather than isolate it.

Human rights groups have raised concerns Sri Lanka has failed to properly investigate troops over allegations they killed up to 40,000 Tamil civilians in the final months of the separatist war in 2009.

There are also concerns about politically-motivated kidnappings and harassment of journalists.

Mr Abbott, who will be in Colombo on Friday after the first week of parliament in Canberra, said he respected the Commonwealth as an institution.

"I certainly don't want us to trash one of the very long-standing and important bodies that we are a senior member of," Mr Abbott said on Monday.

"What Tony Abbott is saying is he is not prepared to jeopardise his accelerated screening process by standing up for human rights," she said.

Sri Lankan immigration authorities briefly detained Australian Greens senator Lee Rhiannon and New Zealand MP Jan Logie at their Colombo hotel on Sunday before they were due to hold a press conference.

They were on a fact-finding mission into alleged rights abuses, and were questioned about alleged visa violations before being allowed to fly home.

"I was very concerned that my liberty was denied to me for more than three hours," Senator Rhiannon said when she arrived back in Sydney on Monday.

She said the Australian delegation shouldn't attend the CHOGM.

"The war crimes need to be investigated; the crimes against humanity clearly continue, the evidence is very strong," she said.

Foreign Affairs Minister Julie Bishop, who will also be in Colombo this week, said she was encouraging all Commonwealth nations to attend the CHOGM and engage with Sri Lanka.

"Progress has been made (on human rights), but there's clearly more to be done," she said.